Source, Etc

Cubebs are the fruits of Piper Cubeba, Linne filius (N.O. Piperaceoe), a dioecious woody climber indigenous to Java, Sumatra, and Borneo, and apparently cultivated also in those islands, although exact information concerning the cultivation is difficult to obtain. The fruits were used as a spice, and as a medicine in the Middle Ages.

Fig. 73.   Piper Cubeba. A, fruiting branch, natural size. C, portion of the same magnified, showing the stalk like elongation of the pericarp. B, branch of staminate plant, natural size. D, bract and stamens, magnified. E, fruit cut to show the endosperm and perisperm, magnified. F, portion of same, more highly magnified, showing the embryo, e, endosperm, a, and perisperm, p. G, Piper nigrum; portion of flowering spike, magnified. (Luerssen.)

Fig. 73. - Piper Cubeba. A, fruiting branch, natural size. C, portion of the same magnified, showing the stalk-like elongation of the pericarp. B, branch of staminate plant, natural size. D, bract and stamens, magnified. E, fruit cut to show the endosperm and perisperm, magnified. F, portion of same, more highly magnified, showing the embryo, e, endosperm, a, and perisperm, p. G, Piper nigrum; portion of flowering spike, magnified. (Luerssen).

The pistillate inflorescence of the cubeb is a spike of sessile flowers. The young fruits are also sessile, but as they mature they become elevated on a slender stalk produced by an abnormal development of the pericarp of the fruit at its base (fig. 73, C). When the fruits are full-grown, but whilst they are still green and unripe, they are stripped from the rachis, bringing with them the stalk-like prolongation of the pericarp which remains permanently attached to them, whence the name ' tailed pepper ' by which they are sometimes known. They are then dried in the sun, during which the green colour changes to a greyish black; they are bought up by Chinese traders and exported chiefly from Batavia to Amsterdam or from Singapore to London.

Description

The commercial drug consists of nearly globular fruits, sometimes depressed at the base (immature fruits), measuring about 4 mm. in diameter, and usually of a greyish brown or nearly black colour. The pericarp is reticulately wrinkled (due to the shrinking as the fresh fruit dries) or, in very young fruits, shrivelled and abruptly prolonged at the base into a slender stalk about 6 mm. in length which is usually rounded or slightly flattened. The apex of the fruit bears the minute remains of three or four stigmas.

Within the pericarp, which is thin and brittle, is a single seed attached by the base; frequently only the dark shrunken remains of a partially developed seed are to be found. The fully developed seed is reddish brown in colour. The embryo is very small and embedded near the apex of the seed in a somewhat scanty endosperm surrounded by a copious, whitish perisperm, which constitutes the greater part of the seed.

Cubebs exhale, when crushed, a strong, characteristic, spicy odour, and possess a strong, spicy, somewhat bitter taste. The crushed fruit, sprinkled upon the surface of concentrated sulphuric acid, produces a crimson coloration. This reaction is an important one, as most of the substitutes for cubebs yield only a brownish red under the same conditions. It is especially valuable when taken in conjunction with the microscopical characters, for there is no substitute known that possesses an anatomical structure identical with that of genuine cubebs, and also yields the crimson colour with sulphuric acid (Hartwich, 1898),

Fig. 74.   Cubeb. A, entire fruit, magnified. B, entire fruit, cut vertically, magnified. (Planchon and Collin.)

Fig. 74. - Cubeb. A, entire fruit, magnified. B, entire fruit, cut vertically, magnified. (Planchon and Collin).

Microscopical Characters

Below the outer epidermis of the pericarp is an interrupted layer consisting of one or two rows of thick-walled sclerenchy-matous cells. Distributed in the thin-walled parenchyma of the mesocarp are numerous large oil-cells. Within the inner epidermis of the pericarp is a second, uninterrupted layer of one or two rows of very thick-walled, radially elongated cells. The seed consists chiefly of perisperm, the cells of which are packed with small starch grains.

The student should observe

(a) The slender stalk, which is not easily detached,

(b) The seed attached only by its base to the pericarp,

(c) The characteristic odour and taste,

(d) The reaction with sulphuric acid.

Constituents

Cubebs yield from 10 to 18 per cent, of volatile oil (sp. gr. 0.910 to 0.930; O.R. -25 ° to -40°), which is contained in oil-cells both in the pericarp and perisperm; similar oil-cells are contained also in the rachis, stem, leaves, etc, but the rachis, which is frequently found mixed with the cubebs, yields only about 1.7 per cent, of volatile oil.

Cubebs contain further an indifferent substance, cubebin, an acid resin, cubebic acid, and an indifferent resin. They afford about 6 (not over 8) per cent. of. ash and yield to ether about 22 (not less than 20) per cent, of oleo-resin.

Cubebin has been obtained in colourless crystals, yielding with sulphuric acid a cherry-red colour; it appears to be devoid of any remarkable physiological action.

Cubebic acid (0.96 per cent.) is white and amorphous; it gives with sulphuric acid a crimson colour, and together with the indifferent resin (2.5 per cent.) produces purely diuretic effects. These two principles may therefore be regarded as active constituents of cubebs.

Cubeb-camphor (C15H14,H10), found in old cubebs, is a crystalline but unstable hydrate of a sesquiterpene.

Adulterations, Etc

The exportation of cubebs has been subject to considerable variation, and during times of scarcity the drug has been liable to adulteration and substitution. Many other plants belonging either to the same or to other natural orders produce fruits resembling cubebs in appearance, a fact which has doubtless facilitated sophistication. Genuine cubebs can, however, be easily distinguished by the crimson colour they impart to sulphuric acid, taken in conjunction with the anatomical characters of the pericarp as above described.

The fact that the fruits on the spike mature in succession from base to apex necessitates the presence in the drug of some immature fruits, but too many of these, which may be recognised by their small size and shrivelled appearance, should not be present. Portions of the rachis also find their way into the commercial drug; they too should not be present in large quantity, as they contain less cubebic acid and resin, and much less volatile oil.

The following fruits have from time to time been found mixed with or substituted for genuine cubebs:

Rinoe badak, greyish, 6 mm. in diameter, odour mace-like.

Piper crassipes, Korthals; black, larger than genuine, stalk longer and curved, usually depressed at base.

Piper ribesioides, Wallich; brown, larger than genuine, taste less aromatic and more bitter, sclerenchymatous cells in mesocarp.

Piper mollissimum, Blume; large fruits, long stalks, no inner row of sclerenchymatous cells.

Piper Lowong, Blume; fruit about 6 mm. in diameter, stalk 6 mm. long, no inner row of sclerenchymatous cells.

Piper Clusii, Casimir de Candolle; small, grey; stalk curved; taste very peppery; imported from the Congo under the name of Congo or African cubebs.

Uses

Cubebs have a stimulant and antiseptic action on the mucous membrane of the genito-urinary organs and are also diuretic. They are chiefly used in gonorrhoea and affections of the bladder, sometimes also in chronic bronchitis, the active constituents of the drug leaving the body by the kidneys and urinary passages, the skin and the respiratory organs.